Field of the Disclosure
The present disclosure relates to a semiconductor device, and in particular it relates to a vertical diode and a method for fabricating a vertical diode.
Description of the Related Art
In general, a diode is composed of P-type semiconductor material and N-type semiconductor material. According to the arrangement of P-type semiconductor material and N-type semiconductor material in the diode, the diodes are classified into two types: the horizontal diode and the vertical diode.
With the same breakdown voltage, the current capacity of the horizontal diode is lower than that of the vertical diode. The current capacity of the horizontal diode may be increased by increasing the effective element area occupied by the horizontal diode. This, however, is undesirable for the scaling down of the semiconductor device.
In order to maintain a high breakdown voltage, the concentration of the dopant in the vertical diode is limited. If the concentration of the dopant is too high, the breakdown voltage will be reduced. However, if the concentration of the dopant is too low, the forward current cannot be significantly increased. Accordingly, in order to increase the forward current and maintain the proper breakdown voltage, there is need in the art for a novel vertical diode and its fabrication method.